[Valgrind-developers] PATCH: Add support for the XLAT instruction

[Adam G. <ar...@cy...>]

the following small patch adds support for the (ancient and horrible)
XLAT instruction. Microsoft in their infinite wisdom use it in their OLE
dispatch code...

Index: coregrind/vg_to_ucode.c
===================================================================
RCS file: /cvsroot/valgrind/valgrind/coregrind/vg_to_ucode.c,v
retrieving revision 1.50
diff -u -r1.50 vg_to_ucode.c
--- coregrind/vg_to_ucode.c     3 Feb 2003 11:25:34 -0000       1.50
+++ coregrind/vg_to_ucode.c     24 Mar 2003 14:56:09 -0000
@@ -4299,6 +4299,25 @@
       codegen_xchg_eAX_Reg ( cb, sz, opc - 0x90 );
       break;
 
+   /* ------------------------ XLAT ----------------------- */
+
+   case 0xD7: /* XLAT */
+      t1 = newTemp(cb); t2 = newTemp(cb);
+      uInstr2(cb, GET, sz, ArchReg, R_EBX, TempReg, t1); /* get eBX */
+      handleSegOverride( cb, sorb, t1 );                 /* make t1 DS:eBX */
+      uInstr2(cb, GET, 1, ArchReg, R_AL, TempReg, t2);   /* get AL */
+      /* Widen %AL to 32 bits, so it's all defined when we add it. */
+      uInstr1(cb, WIDEN, 4, TempReg, t2);
+      LAST_UINSTR(cb).extra4b = 1;
+      LAST_UINSTR(cb).signed_widen = False;
+      uInstr2(cb, ADD, sz, TempReg, t2, TempReg, t1);    /* add AL to eBX */
+      uInstr2(cb, LOAD, 1, TempReg, t1,  TempReg, t2);   /* get byte at t1 into t2 */
+      uInstr2(cb, PUT, 1, TempReg, t2, ArchReg, R_AL);   /* put byte into AL */
+
+      if (dis)
+            VG_(printf)("xlat%c [ebx]\n", nameISize(sz));
+      break;
+
    /* ------------------------ (Grp1 extensions) ---------- */
 
    case 0x80: /* Grp1 Ib,Eb */



Seeya,
 Adam
--
Real Programmers don't comment their code. If it was hard to write,
it should be hard to read, and even harder to modify.
These are all my own opinions.